The present invention relates generally to radiation detectors and methods. More specifically, the present invention relates to methods and assemblies for selectively removing a portion of a resin coating from a scintillation detector.
Scintillation spectrometers are widely used in detection and spectroscopy of energetic photons (e.g., X-rays and γ-rays). Such detectors are commonly used, for example, in nuclear and particle physics research, medical imaging, diffraction, non destructive testing, nuclear treaty verification and safeguards, nuclear non-proliferation monitoring, and geological exploration.
A wide variety of scintillators are now available and new scintillator compositions are being developed. Among currently available scintillators, thallium-doped alkali halide scintillators have proven useful and practical in a variety of applications. One example includes thallium doped cesium iodide (CsI(Tl)), which is a highly desired material for a wide variety of medical and industrial applications due to its excellent detection properties, low cost, and easy availability. Having a high conversion efficiency, a rapid initial decay, an emission in the visible range, and cubic structure that allows fabrication into micro-columnar films (see, e.g., U.S. Pat. No. 5,171,996), CsI(Tl) has found use in radiological imaging applications. Furthermore, its high density, high atomic number, and transparency to its own light make CsI(Tl) a material of choice for x-ray and gamma ray spectroscopy, homeland security applications, and nuclear medicine applications such as intra-operative surgical probes and Single Photon Emission Computed Tomography or SPECT.
Scintillation spectrometry generally comprises a multi-step scheme. Specifically, scintillators work by converting energetic photons such as X-rays, gamma-rays, and the like, into a more easily detectable signal (e.g., visible light). Thus, incident energetic photons are stopped by the scintillator material of the device and, as a result, the scintillator produces light photons mostly in the visible light range that can be detected, e.g., by a suitably placed photodetector. Various possible scintillator detector configurations are known. In general, scintillator based detectors typically include a scintillator material optically coupled to a photodetector. In many instances, scintillator material is incorporated into a radiation detection device by first depositing the scintillator material on a suitable substrate. A suitable substrate can include a photodetector or a portion thereof, or a separate scintillator panel is fabricated by depositing scintillator on a passive substrate, which is then incorporated into a detection device.
In addition to scintillator material, additional coatings, such as those including organic resins and polymers, are often deposited on scintillator detectors for various reasons. Some resin coatings, for example, have properties such that the resin coating acts as a protective coating with respect to nearby or adjacent layers (e.g., substrate, scintillator, etc.). Typically, when a resin coating is deposited on a scintillator detector assembly, the resin will coat many, if not all, of the exposed surface of the assembly, including portions of the assembly where coating may not necessarily be desired. As such, selective removal of portions of the coating is often required.
Unfortunately, resin coating can often coat sensitive, delicate, and/or expensive components of the scintillator detector assembly. While the coating itself may not damage the detector assembly components, significant damage is often sustained in the process of removing the coating from the components. For example, certain commonly used resin films adhere strongly to the detector, are resilient, and not easily removed in a controlled manner. To avoid damage to the detector or inaccurate removal of the wrong portions of resin films caused by simply tearing the resin films from the detector, current practice typically includes careful cutting and removal of the film. However, since the coating is often present on very sensitive components including, for example, the detectors electrical components, errors common in the cutting and removal process often result in damaged detector components, thereby decreasing yields in detector manufacturing and assembly, and greatly increasing costs.
Thus, there is a need for improved techniques and methods, as well as tools and assemblies, for removing portions of resin coatings deposited on scintillation detectors. In particular, methods and assemblies are needed for selectively removing portions of resin coatings from detectors in a controlled and accurate manner, and by avoiding the damage often inflicted by current removal methods.